Power door lock systems in which an operator need do nothing more than push a button to lock or unlock a vehicle door have been in use for some time. There are several design choices for the actuator. Solenoids are possible, but are often too loud. Therefore, electric motor drives have found increasing acceptance. A potential drawback of motor drives is that if the motor drive shaft and lock rod are directly interconnected, manual operation of the lock rod would back drive the motor. Therefore, many designs for centrifugal clutches and for lost motion devices have been proposed. No proposal has met with complete commercial acceptance, and the search is always on for new and different actuators to solve the motor back drive problem.